Bayley Scales of Infant Development

A comprehensive developmental test for infants and toddlers from two to 30 months of age.

The Bayley Scales of Infant Development measure mental and physical, as well as emotional and social, development. The test, which takes approximately 45 minutes, is administered individually by having the child respond to a series of stimuli. The Mental Scales, which measure intellectual development, assess functions such as memory, learning, problem-solving ability, and verbal communication skills. The Motor Scales evaluate the child's ability to sit and stand, perform other activities requiring coordination of the large muscles (gross motor skills), and perform more delicate manipulations with fingers and hands (fine motor skills). Finally, the Infant Behavior Record (IBR) assesses the child's social and emotional development through a standardized description of his or her behavior during the testing session. Scores are measured against norms for each of the 14 different age groups. Often, the Bayley scales are used to determine whether a child is developing normally and provide for early diagnosis and intervention in cases of developmental delay, where there is significant tardiness in acquiring certain skills or performing key activities. Additionally, they can be used to qualify a child for special services and/or demonstrate the effectiveness of those services. Most recently, the Bayley scales have been used to insure compliance with legislation that requires identification of at-risk children and provision of services for them.